Photoresist and method

ABSTRACT

Shrinkage and mass losses are reduced in photoresist exposure and post exposure baking by utilizing a small group which will decompose. Alternatively a bulky group which will not decompose or a combination of the small group which will decompose along with the bulky group which will not decompose can be utilized. Additionally, polar functional groups may be utilized in order to reduce the diffusion of reactants through the photoresist.

PRIORITY CLAIM AND CROSS-REFERENCE

This application claims priority to and is a divisional of U.S. patentapplication Ser. No. 14/334,612 entitled “Photoresist and Method” andfiled on Jul. 17, 2014, which claims the benefit of U.S. ProvisionalApplication No. 61/912,967, filed on Dec. 6, 2013, and entitled“Negative Tone Developer Photoresist and Device Manufactured UsingSame,” which applications are incorporated herein by reference.

Additionally, this application is related to U.S. Pat. No. 9,581,908entitled “Photoresist and Method,” filed on Jul. 17, 2014 and issued onFeb. 28, 2017, which application is hereby incorporated herein byreference.

BACKGROUND

As consumer devices have gotten smaller and smaller in response toconsumer demand, the individual components of these devices havenecessarily decreased in size as well. Semiconductor devices, which makeup a major component of devices such as mobile phones, computer tablets,and the like, have been pressured to become smaller and smaller, with acorresponding pressure on the individual devices (e.g., transistors,resistors, capacitors, etc.) within the semiconductor devices to also bereduced in size.

One enabling technology that is used in the manufacturing processes ofsemiconductor devices is the use of photolithographic materials. Suchmaterials are applied to a surface and then exposed to an energy thathas itself been patterned. Such an exposure modifies the chemical andphysical properties of the exposed regions of the photolithographicmaterial. This modification, along with the lack of modification inregions of the photolithographic material that were not exposed, can beexploited to remove one region without removing the other.

However, as the size of individual devices has decreased, processwindows for photolithographic processing have become tighter andtighter. As such, advances in the field of photolithographic processinghave been necessitated in order to keep up the ability to scale down thedevices, and further improvements are needed in order to meet thedesired design criteria such that the march towards smaller and smallercomponents may be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a substrate with a layer to be patterned and aphotoresist in accordance with some embodiments;

FIG. 2 illustrates a photoresist with a small group which will decomposein accordance with some embodiments;

FIG. 3 illustrates a photoresist with a bulky group which will notdecompose in accordance with some embodiments;

FIG. 4 illustrates a photoresist with a bulky group which will notdecompose and a small group which will decompose in accordance with someembodiments;

FIG. 5 illustrates a photoresist with a polar functional group inaccordance with some embodiments;

FIG. 6 illustrates an exposure of the photoresist in accordance withsome embodiments;

FIG. 7 illustrates a development of the photoresist in accordance withsome embodiments; and

FIG. 8 illustrates a removal of a developer in accordance with someembodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

With reference now to FIG. 1, there is shown a semiconductor device 100with a substrate 101, active devices 103 on the substrate 101, aninterlayer dielectric (ILD) layer 105 over the active devices 103,metallization layers 107 over the ILD layer 105, a layer to be patterned109 over the ILD layer 105, and a photoresist 111 over the layer to bepatterned 109. The substrate 101 may comprise bulk silicon, doped orundoped, or an active layer of a silicon-on-insulator (SOI) substrate.Generally, an SOI substrate comprises a layer of a semiconductormaterial such as silicon, germanium, silicon germanium, SOI, silicongermanium on insulator (SGOI), or combinations thereof. Other substratesthat may be used include multi-layered substrates, gradient substrates,or hybrid orientation substrates.

The active devices 103 are represented in FIG. 1 as a single transistor.However, as one of skill in the art will recognize, a wide variety ofactive devices such as capacitors, resistors, inductors and the like maybe used to generate the desired structural and functional requirementsof the design for the semiconductor device 100. The active devices 103may be formed using any suitable methods either within or else on thesurface of the substrate 101.

The ILD layer 105 may comprise a material such as boron phosphoroussilicate glass (BPSG), although any suitable dielectrics may be used foreither layer. The ILD layer 105 may be formed using a process such asPECVD, although other processes, such as LPCVD, may alternatively beused. The ILD layer 105 may be formed to a thickness of between about100 Å and about 3,000 Å.

The metallization layers 107 are formed over the substrate 101, theactive devices 103, and the ILD layer 105 and are designed to connectthe various active devices 103 to form functional circuitry. Whileillustrated in FIG. 1 as a single layer, the metallization layers 107are formed of alternating layers of dielectric and conductive materialand may be formed through any suitable process (such as deposition,damascene, dual damascene, etc.). In an embodiment there may be fourlayers of metallization separated from the substrate 101 by the ILDlayer 105, but the precise number of metallization layers 107 isdependent upon the design of the semiconductor device 100.

A layer to be patterned 109 or otherwise processed using the photoresist111 is formed over the metallization layers 107. The layer to bepatterned 109 may be an upper layer of the metallization layers 107 orelse may be a dielectric layer (such as a passivation layer) formed overthe metallization layers 107. In an embodiment in which the layer to bepatterned 109 is a metallization layer, the layer to be patterned 109may be formed of a conductive material using processes similar to theprocesses used for the metallization layers (e.g., damascene, dualdamascene, deposition, etc.). Alternatively, if the layer to bepatterned 109 is a dielectric layer the layer to be patterned 109 may beformed of a dielectric material using such processes as deposition,oxidation, or the like.

However, as one of ordinary skill in the art will recognize, whilematerials, processes, and other details are described in theembodiments, these details are merely intended to be illustrative ofembodiments, and are not intended to be limiting in any fashion. Rather,any suitable layer, made of any suitable material, by any suitableprocess, and any suitable thickness, may alternatively be used. All suchlayers are fully intended to be included within the scope of theembodiments.

The photoresist 111 is applied to the layer to be patterned 109. In anembodiment the photoresist 111 includes a polymer resin along with oneor more photoactive compounds (PACs) in a solvent. The polymer resin andthe PACs within the solvent are applied to the layer to be patterned 109and a pre-exposure bake is performed in order to heat and drive off thesolvent in order to remove the solvent and leave behind the polymerresin and the PACs for exposure.

FIG. 2 illustrates one embodiment of the polymer resin that may be usedfor the photoresist 111. In this embodiment the polymer resin maycomprise a hydrocarbon structure (such as a alicyclic hydrocarbonstructure, represented in FIG. 2 within the dashed box 201) thatcontains one or more bulky groups that will decompose (or cleavage,e.g., acid leaving groups, represented in FIG. 2 within the dashed box203) or otherwise react when mixed with acids, bases, or free radicalsgenerated by the PACs (as further described below). In an embodiment thehydrocarbon structure 201 comprises a repeating unit that forms askeletal backbone of the polymer resin. This repeating unit may includeacrylic esters, methacrylic esters, crotonic esters, vinyl esters,maleic diesters, fumaric diesters, itaconic diesters,(meth)acrylonitrile, (meth)acrylamides, styrenes, vinyl ethers,combinations of these, or the like.

Specific structures which may be utilized for the repeating unit of thehydrocarbon structure 201 include methyl acrylate, ethyl acrylate,n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutylacrylate, tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate,acetoxyethyl acrylate, phenyl acrylate, 2-hydroxyethyl acrylate,2-methoxyethyl acrylate, 2-ethoxyethyl acrylate,2-(2-methoxyethoxy)ethyl acrylate, cyclohexyl acrylate, benzyl acrylate,2-alkyl-2-adamantyl (meth)acrylate or dialkyl(1-adamantyl)methyl(meth)acrylate, methyl methacrylate, ethyl methacrylate, n-propylmethacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, tert-butyl methacrylate, n-hexyl methacrylate,2-ethylhexyl methacrylate, acetoxyethyl methacrylate, phenylmethacrylate, 2-hydroxyethyl methacrylate, 2-methoxyethyl methacrylate,2-ethoxyethyl methacrylate, 2-(2-methoxyethoxy)ethyl methacrylate,cyclohexyl methacrylate, benzyl methacrylate, 3-chloro-2-hydroxypropylmethacrylate, 3-acetoxy-2-hydroxypropyl methacrylate,3-chloroacetoxy-2-hydroxypropyl methacrylate, butyl crotonate, hexylcrotonate and the like. Examples of the vinyl esters include vinylacetate, vinyl propionate, vinyl butylate, vinyl methoxyacetate, vinylbenzoate, dimethyl maleate, diethyl maleate, dibutyl maleate, dimethylfumarate, diethyl fumarate, dibutyl fumarate, dimethyl itaconate,diethyl itaconate, dibutyl itaconate, acrylamide, methyl acrylamide,ethyl acrylamide, propyl acrylamide, n-butyl acrylamide, tert-butylacrylamide, cyclohexyl acrylamide, 2-methoxyethyl acrylamide, dimethylacrylamide, diethyl acrylamide, phenyl acrylamide, benzyl acrylamide,methacrylamide, methyl methacrylamide, ethyl methacrylamide, propylmethacrylamide, n-butyl methacrylamide, tert-butyl methacrylamide,cyclohexyl methacrylamide, 2-methoxyethyl methacrylamide, dimethylmethacrylamide, diethyl methacrylamide, phenyl methacrylamide, benzylmethacrylamide, methyl vinyl ether, butyl vinyl ether, hexyl vinylether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether and thelike. Examples of the styrenes include styrene, methyl styrene, dimethylstyrene, trimethyl styrene, ethyl styrene, isopropyl styrene, butylstyrene, methoxy styrene, butoxy styrene, acetoxy styrene, chlorostyrene, dichloro styrene, bromo styrene, vinyl methyl benzoate,α-methyl styrene, maleimide, vinylpyridine, vinylpyrrolidone,vinylcarbazole, combinations of these, or the like.

In an embodiment the repeating unit of the hydrocarbon structure 201 mayalso have either a monocyclic or a polycyclic hydrocarbon structuresubstituted into it, or else the monocyclic or polycyclic hydrocarbonstructure may be the repeating unit, in order to form an alicyclichydrocarbon structure. Specific examples of monocyclic structures thatmay be used include bicycloalkane, tricycloalkane, tetracycloalkane,cyclopentane, cyclohexane, or the like. Specific examples of polycyclicstructures that may be used include cycloalkane, adamantine, adamantine,norbornane, isobornane, tricyclodecane, tetracycododecane, or the like.

The bulky group which will decompose 203, otherwise known as a bulkyleaving group or, in an embodiment in which the PAC is a photoacidgenerator, a bulky acid leaving group, is attached to the hydrocarbonstructure 201 so that it will react with the acids/bases/free radicalsgenerated by the PACs during exposure. In an embodiment the bulky groupwhich will decompose 203 may be a carboxylic acid group, a fluorinatedalcohol group, a phenolic alcohol group, a sulfonic group, a sulfonamidegroup, a sulfonylimido group, an (alkylsulfonyl)(alkylcarbonyl)methylene group, an (alkylsulfonyl)(alkyl-carbonyl)imidogroup, a bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imidogroup, a bis(alkylsylfonyl)methylene group, a bis(alkylsulfonyl)imidogroup, a tris(alkylcarbonyl methylene group, atris(alkylsulfonyl)methylene group, combinations of these, or the like.Specific groups that may be utilized for the fluorinated alcohol groupinclude fluorinated hydroxyalkyl groups, such as a hexafluoroisopropanolgroup. Specific groups that may be utilized for the carboxylic acidgroup include acrylic acid groups, methacrylic acid groups, or the like.

In an embodiment the bulky group which will decompose 203 has greaterthan nine carbon atoms and comprises greater than about 45% of theloading (the available sites on the hydrocarbon backbone which mayreceive functional groups such as the bulky group which will decompose203). However, while the percentage of loading is provided as anillustrative example, the loading described herein is not intended to belimiting, as any suitable loading may alternatively be utilized.

Additionally, the polymer resin may also contain a small group whichwill decompose monomer (represented in FIG. 2 by the dashed box labeled211) with a small group which will decompose (represented in FIG. 2 bythe dashed box labeled 209). In such an embodiment the small group whichwill decompose monomer 211 may have the following structure:

Wherein Ra, Rb, and Rc each independently represent a group selectedfrom the group consisting of a C1˜C5 alkyl group, a cycloalkyl group, ahydroxylalkyl group, an alkoxy group, an alkoxyl alkyl group, anactcetyl group, an acetylalkyl group, a carboxyl group, an alkylcarboxyl group, a cycloalky group, and a heterocycloalkyl group, oradjacent group may be bonded to each other to form a C3˜C9 saturated orunsaturated hydrocarbon ring or a C3-C9 heterocycylic group. Thestructure can be long a chain, cyclic, or a 3D structure. In particularembodiments, the small group which will decompose may have less thannine carbon atoms.

Specific structures that may be utilized for the small group which willdecompose monomer 211 with the small group which will decompose 209include the following:

Wherein Rd is a C0-C3 alkyl group.

In an embodiment the small group which will decompose monomer 211 maycomprise greater than 5% of the monomers within the polymer resin.However, such a number is intended to only be illustrative and is notintended to be limiting to the current embodiments. Rather, any suitableamount of the small group which will decompose monomer 211 may beutilized in an effort to reduce the shrinkage of the photoresist 111.

By utilizing the small group which will decompose monomer 211, the smallgroup which will decompose monomer 211 will react with the PACs and forma leaving group, such as an acid leaving group, which will degas alongwith the leaving group from the bulky group which will decompose 203,thereby changing the solubility of the polymer resin in the region ofexposure. However, because the small group which will decompose monomer211 has the small group which will decompose 209 which has a fewernumber of atoms on it than the bulky group which will decompose 203, theamount of mass that leaves the photoresist 111 is reduced, therebyminimizing any shrinkage and deterioration of critical dimensions thatresult from the degassing.

In an embodiment the polymer resin may optionally also comprise othergroups attached to the hydrocarbon structure 201 that help to improve avariety of properties of the polymerizable resin. For example, inclusionof a lactone group (represented in FIG. 2 within dashed box 205) to thehydrocarbon structure 201 assists to reduce the amount of line edgeroughness after the photoresist 111 has been developed, thereby helpingto reduce the number of defects that occur during development. In anembodiment the lactone groups 205 may include rings having five to sevenmembers, although any suitable lactone structure may alternatively beused for the lactone group 205, and the lactone group 205 may have aloading on the hydrocarbon backbone of between about 30% and about 70%.

In particular embodiments the lactone group 205 may comprise thefollowing structures:

Wherein Re may represent C1-C8 alkyl group, a C4-C7 cycloalkyl group, aC1-C8 alkoxy group, a C2-C8 alkoxycarbonyl group, a carboyxl group, ahalogen atom, a hydroxyl group, a cyano group, or a group which willdecompose. Further, the lactone group may not have the Re group, or mayhave multiple Re groups bound together, wherein each of the Re groupsmay be the same or different from each other, in either a linear orcyclic structure.

The polymer resin may also optionally comprise groups that can assist inincreasing the adhesiveness of the photoresist 111 (represented in FIG.2 within the dashed box labeled 207) to underlying structures (e.g., thelayer to be patterned 109). In an embodiment polar groups may be used tohelp increase the adhesiveness, and polar groups that may be used inthis embodiment include hydroxyl groups, cyano groups, or the like,although any suitable polar group may alternatively be utilized. In anembodiment the group which assists in increasing the adhesiveness 207may have a loading on the hydrocarbon backbone of less than about 20%.

The various groups desired within the polymer resin are then combined toform the polymer resin. In a particular embodiment, the various groups,such as the monomers with the small group which will decompose monomer211, a monomer with the bulky group which will decompose 203, theadhesive group 207, the lactone group 205, and any other desiredmonomers will be polymerized with one another using, e.g., a radicalpolymerization, to form a polymer structure with the carbon chainbackbone for the polymer resin.

FIG. 3 illustrates another embodiment in which, instead of adding asmall group which will decompose monomer 211 (not illustrated in FIG. 3but illustrated and described above with respect to FIG. 2), a bulkygroup which will not decompose (represented in FIG. 3 by R₁ and thedashed box 301) is added to the polymer resin. In this embodiment thebulky group which will not decompose 301 may be an alkyl chain, an alkylring, or a three-dimensional alkyl structure with between nine andthirty carbon atoms, such as between eleven and thirty carbon atoms, oreven between fourteen and thirty carbon atoms. In particularembodiments, suitable structures for the bulky group which will notdecompose 301 include:

Wherein A represents a group selected from the group consisting of aC0˜C8 alkanediyl group, a C1-C8 heteroalkanediyl group, a C2-C9heteroalkenediyl group, a C3-C9 cycloalkenediyl group, a C2-C20heterocycloalkanediyl group, or a C3-C9 heterocycloalkeneduyl group; R22is a bulky unit with C2-C30 alkyl group, cycloalkyl group, hydroxylalkylgroup, alkoxy group, alkoxyl alkyl group, acetyl group, acetylalkylgroup, carboxyl group, alky caboxyl group, cycloalkyl carboxyl group,C2˜C30 saturated or unsaturated hydrocarbon ring, or C2-C30 heterocyclicgroup which can be a chain, a ring, a 3-D structure (adamantyl forexample), a cyclic to polymer backbone structure; and X is hydrogen, amethyl group, or R22.

In an embodiment in which the bulky group which will not decompose 301has a cyclic structure bonded to the polymer backbone, the bulky groupwhich will not decompose 301 may have the following structure:

Wherein A and R22 are as described above.

In specific embodiments in which A is C0, the bulky group which will notdecompose 301 may comprise the following structures:

In an embodiment the bulky group which will not decompose 301 may have aloading on the hydrocarbon backbone of greater than about 5%. However,this loading is only intended to be illustrative and is not intended tobe limiting upon the present embodiments. Rather, any suitable loadingthat will assist in the reduction of shrinkage and critical dimensionloss may alternatively be utilized, and all such loadings are fullyintended to be included within the scope of the embodiments.

By adding the bulky group which will not decompose 301 to thehydrocarbon backbone, additional mass that will not be cleaved from thehydrocarbon backbone may be added in order to compensate for the mass ofthe bulky group which will decompose 203 that will be lost. Bycompensating for the mass that will be lost, overall shrinkage and lossof critical dimension may be reduced and mitigated. As such, smaller andsmaller dimensions may be imaged.

FIG. 4 illustrates yet another embodiment of a photoresist that may beused. In this embodiment the bulky group which will not decompose 301(again represented in FIG. 4 by the designation R₁) is placed within thepolymer resin, and a cleavage unit is bonded to the bulky group whichwill not decompose 301 (as illustrated within FIG. 4 by the dashed boxlabeled 401). In a particular example, and as illustrated in FIG. 4, thesmall group which will decompose 209 may be bonded to the bulky groupwhich will not decompose 301. In such an embodiment, the monomer inwhich the bulky group which will not decompose 301 is bonded to thesmall group which will decompose 209 may have one of the followingstructures:

Wherein A represents a group selected from the group consisting of aC0-C8 alkanediyl group, a C1-C8 heteroalkanediyl group, a C2-C9heteroalkenediyl group, a C3-C9 cycloalkenediyl group, a C2-C20heterocycloalkanediyl group, or a C3-C9 heterocycloalkeneduyl group andR22 is a bulky unit with C2-C30 alkyl group, cycloalkyl group,hydroxylalkyl group, alkoxy group, alkoxyl alkyl group, acetyl group,acetylalkyl group, carboxyl group, alky caboxyl group, cycloalkylcarboxyl group, C2-C30 saturated or unsaturated hydrocarbon ring, orC2-C30 heterocyclic group which can be chain, ring, 3-D structure(adamantyl for example), cyclic to polymer backbone structure; X ishydrogen, a methyl group, or R22. Ra, Rb, and Rc are as described abovewith respect to the small group which will decompose 209 (described inFIG. 2).

In an embodiment in which the monomer in which the bulky group whichwill not decompose 301 is bonded to the small group which will decompose209 has a cyclic structure bonded to the polymer backbone, the monomerin which the bulky group which will not decompose 301 is bonded to thesmall group which will decompose 209 may have the following structures:

Wherein A, R22, Ra, Rb, and Rc are as described above.

In a particular embodiment, the monomer which comprises the small groupwhich will not decompose 209 bonded to the bulky group which will notdecompose 301 may have the following structure:

In an embodiment the overall loading of the combined bulky group whichwill not decompose 301 and the small group which will decompose 209 maybe greater than about 5% of the overall loading on the hydrocarbonbackbone. However, this loading is only intended to be illustrative andis not intended to be limiting upon the present embodiments. Rather, anysuitable loading that will assist in the reduction of shrinkage andcritical dimension loss may alternatively be utilized, and all suchloadings are fully intended to be included within the scope of theembodiments.

By attaching the small group which will decompose 209 to the bulky groupwhich will not decompose 301, the mass loss from the small group whichwill decompose 209 and the bulky group which will decompose 203 may becompensated. This compensation will reduce or mitigate the overall massloss during degassing during and after exposure and post-exposurebaking. Such a reduction will allow for a reduction in shrinkage andcritical dimension losses, thereby allowing smaller imaging dimensionsto be realized.

In an alternative embodiment, instead of attaching the small group whichwill decompose 209 to the bulky group which will not decompose 301,another cleavage unit, such as the bulky group which will decompose 203,may be attached to the bulk group which will not decompose 301. Anysuitable unit that will cleavage may alternatively be utilized andbonded to the bulky group which will not decompose 301, and all suchunits are fully intended to be included within the scope of theembodiments.

FIG. 5 illustrates yet another embodiment similar to the embodiment inFIG. 4, but in which the small group which will decompose 209 isreplaced on the bulky group which will not decompose 301 by a polarfunctional group (represented in FIG. 5 by the designation R₂ labeled501). In an embodiment a monomer which comprises the polar functionalgroup 501 bonded to the bulky group which will not decompose 301 mayhave a structure such as:

Wherein A represents a group selected from the group consisting of aC0-C8 alkanediyl group, a C1-C8 heteroalkanediyl group, a C2-C9heteroalkenediyl group, a C3-C9 cycloalkenediyl group, a C2-C20heterocycloalkanediyl group, or a C3-C9 heterocycloalkeneduyl group andR22 is a bulky unit with C2-C30 alkyl group, cycloalkyl group,hydroxylalkyl group, alkoxy group, alkoxyl alkyl group, acetyl group,acetylalkyl group, carboxyl group, alky caboxyl group, cycloalkylcarboxyl group, C2-C30 saturated or unsaturated hydrocarbon ring, orC2-C30 heterocyclic group which can be chain, ring, 3-D structure(adamantyl for example), cyclic to polymer backbone structure; andwherein R33 represents one of the following:R₄—OHR₅COOR₆R₇(OH)₂Wherein R₄, R₅, R₆, and R₇ may each have be an alkyl chain, an alkylcyclic structure, or an alkyl three-dimensional structure with between 2carbon atoms and 20 carbon atoms. In a particular embodiment the polarfunctional group may be adamantyl, although any other suitable polarfunctional group may alternatively be utilized.

Alternatively, the polar functional group 501 may comprise the lactonegroup 205, as discussed above with respect to FIG. 2. Any suitable polargroup may be utilized for this embodiment, and all such groups are fullyintended to be included within the scope of the embodiments.

In an embodiment in which the monomer in which the bulky group whichwill not decompose 301 is bonded to the polar functional group 501 has acyclic structure bonded to the polymer backbone, the monomer in whichthe bulky group which will not decompose 301 is bonded to the polarfunctional group 501 may have the following structure:

Wherein A, R22 and R33 are as described above.

In an embodiment the loading for the combination of the bulky groupwhich will not decompose 301 and the polar functional group 501 may begreater than about 5% of the overall loading on the hydrocarbonbackbone. However, this loading is only intended to be illustrative andis not intended to be limiting upon the present embodiments. Rather, anysuitable loading that will assist in the reduction of shrinkage andcritical dimension loss may alternatively be utilized, and all suchloadings are fully intended to be included within the scope of theembodiments.

By adding the polar functional group 501 to the bulky group which willnot decompose 301, the polar functional group 501 will reduce or retardthe diffusion of the acids/bases/free radicals generated during theexposure process. Such a reduction of the diffusion will work to reduceundesired reactions outside of the exposed region 601, thereby furtherpreventing any undesired reactions and the subsequent degassing. Byreducing the degassing, shrinkage and critical dimension loss may bereduced and smaller items may be imaged.

Returning now to FIG. 1, additionally, the photoresist 111 alsocomprises one or more PACs. The PACs may be photoactive components suchas photoacid generators, photobase generators, free-radical generators,or the like, and the PACs may be positive-acting or negative-acting. Inan embodiment in which the PACs are a photoacid generator, the PACs maycomprise halogenated triazines, onium salts, diazonium salts, aromaticdiazonium salts, phosphonium salts, sulfonium salts, iodonium salts,imide sulfonate, oxime sulfonate, diazodisulfone, disulfone,o-nitrobenzylsulfonate, sulfonated esters, halogenerated sulfonyloxydicarboximides, diazodisulfones, α-cyanooxyamine-sulfonates,imidesulfonates, ketodiazosulfones, sulfonyldiazoesters,1,2-di(arylsulfonyl)hydrazines, nitrobenzyl esters, and the s-triazinederivatives, suitable combinations of these, and the like.

Specific examples of photoacid generators that may be used includeα-(trifluoromethylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarbo-ximide(MDT), N-hydroxy-naphthalimide (DDSN), benzoin tosylate,t-butylphenyl-α-(p-toluenesulfonyloxy)-acetate andt-butyl-α-(p-toluenesulfonyloxy)-acetate, triarylsulfonium anddiaryliodonium hexafluoroantimonates, hexafluoroarsenates,trifluoromethanesulfonates, iodonium perfluorooctanesulfonate,N-camphorsulfonyloxynaphthalimide,N-pentafluorophenylsulfonyloxynaphthalimide, ionic iodonium sulfonatessuch as diaryl iodonium (alkyl or aryl) sulfonate andbis-(di-t-butylphenyl)iodonium camphanylsulfonate,perfluoroalkanesulfonates such as perfluoropentanesulfonate,perfluorooctanesulfonate, perfluoromethanesulfonate, aryl (e.g., phenylor benzyl) triflates such as triphenylsulfonium triflate orbis-(t-butylphenyl)iodonium triflate; pyrogallol derivatives (e.g.,trimesylate of pyrogallol), trifluoromethanesulfonate esters ofhydroxyimides, α,α′-bis-sulfonyl-diazomethanes, sulfonate esters ofnitro-substituted benzyl alcohols, naphthoquinone-4-diazides, alkyldisulfones, and the like.

In an embodiment in which the PACs are a free-radical generator, thePACs may comprise n-phenylglycine, aromatic ketones such asbenzophenone, N,N′-tetramethyl-4,4′-diaminobenzophenone,N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzo-phenone,3,3′-dimethyl-4-methoxybenzophenone,p,p′-bis(dimethylamino)benzo-phenone,p,p′-bis(diethylamino)-benzophenone, anthraquinone,2-ethylanthraquinone, naphthaquinone and phenanthraquinone, benzoinssuch as benzoin, benzoinmethylether, benzoinethylether,benzoinisopropylether, benzoin-n-butylether, benzoin-phenylether,methylbenzoin and ethybenzoin, benzyl derivatives such as dibenzyl,benzyldiphenyldisulfide and benzyldimethylketal, acridine derivativessuch as 9-phenylacridine and 1,7-bis(9-acridinyl)heptane, thioxanthonessuch as 2-chlorothioxanthone, 2-methylthioxanthone,2,4-diethylthioxanthone, 2,4-dimethylthioxanthone and2-isopropylthioxanthone, acetophenones such as 1,1-dichloroacetophenone,p-t-butyldichloro-acetophenone, 2,2-diethoxyacetophenone,2,2-dimethoxy-2-phenylacetophenone, and2,2-dichloro-4-phenoxyacetophenone, 2,4,5-triarylimidazole dimers suchas 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer,2-(o-chlorophenyl)-4,5-di-(m-methoxyphenyl imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer,2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl), 5-phenylimidazole dimer,2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer and 2-(p-methylmercaptophenyl)-4,5-diphenylimidazole dimmer, suitable combinations ofthese, or the like.

In an embodiment in which the PACs are a photobase generator, the PACsmay comprise quaternary ammonium dithiocarbamates, a aminoketones,oxime-urethane containing molecules such as dibenzophenoneoximehexamethylene diurethan, ammonium tetraorganylborate salts, andN-(2-nitrobenzyloxycarbonyl) cyclic amines, suitable combinations ofthese, or the like. However, as one of ordinary skill in the art willrecognize, the chemical compounds listed herein are merely intended asillustrated examples of the PACs and are not intended to limit theembodiments to only those PACs specifically described. Rather, anysuitable PAC may alternatively be utilized, and all such PACs are fullyintended to be included within the scope of the present embodiments.

The individual components of the photoresist 111 may be placed into asolvent in order to aid in the mixing and placement of the photoresist111. To aid in the mixing and placement of the photoresist 111, thesolvent is chosen at least in part based upon the materials chosen forthe polymer resin as well as the PACs. In particular, the solvent ischosen such that the polymer resin and the PACs can be evenly dissolvedinto the solvent and dispensed upon the layer to be patterned 109.

In an embodiment the solvent may be an organic solvent, and may compriseany suitable solvent such as ketones, alcohols, polyalcohols, ethers,glycol ethers, cyclic ethers, aromatic hydrocarbons, esters,propionates, lactates, lactic esters, alkylene glycol monoalkyl ethers,alkyl lactates, alkyl alkoxypropionates, cyclic lactones, monoketonecompounds that contain a ring, alkylene carbonates, alkyl alkoxyacetate,alkyl pyruvates, lactate esters, ethylene glycol alkyl ether acetates,diethylene glycols, propylene glycol alkyl ether acetates, alkyleneglycol alkyl ether esters, alkylene glycol monoalkyl esters, or thelike.

Specific examples of materials that may be used as the solvent for thephotoresist 111 include acetone, methanol, ethanol, toluene, xylene,4-hydroxy-4-methyl-2-pentatone, tetrahydrofuran, methyl ethyl ketone,cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol,ethylene glycol monoacetate, ethylene glycol dimethyl ether, ethyleneglycol dimethyl ether, ethylene glycol methylethyl ether, ethyleneglycol monoetheryl ether, methyl celluslve acetate, ethyl cellosolveacetate, diethylene glycol, diethylene glycol monoacetate, diethyleneglycol monomethyl ether, diethylene glycol diethyl ether, diethyleneglycol dimethyl ether, diethylene glycol ethylmethyl ether, dietheryleneglycol monoethyl ether, diethylene glycol monbutyl ether, ethyl2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate,methyl 2-hydroxy-2-methylbutanate, methyl 3-methoxypropionate, ethyl3-methoxypropionate, methyl 3-ethoxypropionate, ethyl3-ethoxypropionate, ethyl acetate, butyl acetate, methyl lactate andethyl lactate, propylene glycol, propylene glycol monoacetate, propyleneglycol monoethyl ether acetate, propylene glycol monomethyl etheracetate, propylene glycol monopropyl methyl ether acetate, propyleneglycol monobutyl ether acetate, propylene glycol monobutyl etheracetate, propylene glycol monomethyl ether propionate, propylene glycolmonoethyl ether propionate, proplyelen glycol methyl ether adcetate,proplylene glycol ethyl ether acetate, ethylene glycol monomethyl etheracetate, ethylene glycol monoethyl ether acetate, propylene glycolmonomethyl ether, propylene glycol monoethyl ether, propylene glycolmonopropyl ether, propylene glycol monobutyl ether, ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, methyl lactate, ethyllactate, propyl lactate, and butyl lactate, ethyl 3-ethoxypropionate,methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl3-methoxypropionate, β-propiolactone, β-butyrolactone, γ-butyrolactone,α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone,γ-caprolactone, γ-octanoic lactone, α-hydroxy-γ-butyrolactone,2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone,4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone,2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone,3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone,2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone,2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone,3-decanone, 4-decanone, 5-hexene-2-one, 3-pentene-2-one, cyclopentanone,2-methylcyclopentanone, 3-methylcyclopentanone,2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone,cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone,4-ethylcyclohexanone, 2,2-dimethylcyclohexanone,2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone,2-methylcycloheptanone, 3-methylcycloheptanone, pylene carbonate,vinylene carbonate, ethylene carbonate, and butylene carbonate,acetate-2-methoxyethyl, acetate-2-ethoxyethyl,acetate-2-(2-ethoxyethoxy)ethyl, acetate-3-methoxy-3-methylbutyl,acetate-1-methoxy-2-propyl, dipropylene glycol, monomethylether,monoethylether, monopropylether, monobutylehter, monopheylether,dipropylene glycol monoacetate, dioxane, methyl lactate, etheyl lactate,methyl acetate, ethyl acetate, butyl acetate, methyl puruvate, ethylpuruvate, propyl pyruvate, methyl methoxypropionate, ethylethoxypropionate, n-methylpyrrolidone (NMP), 2-methoxyethyl ether(diglyme), ethylene glycol monom-ethyl ether, propylene glycolmonomethyl ether; ethyl lactate or methyl lactate, methyl proponiate,ethyl proponiate and ethyl ethoxy proponiate, methylethyl ketone,cyclohexanone, 2-heptanone, carbon dioxide, cyclopentatone,cyclohexanone, ethyl 3-ethocypropionate, ethyl lactate, propylene glycolmethyl ether acetate (PGMEA), methylene cellosolve, butyle acetate, and2-ethoxyethanol, N-methylformamide, N,N-dimethylformamide,N-methylformanilide, N-methylacetamide, N,N-dimethylacetamide,N-methylpyrrolidone, dimethylsulfoxide, benzyl ethyl ether, dihexylether, acetonylacetone, isophorone, caproic acid, caprylic acid,1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate,diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate,propylene carbonate, phenyl cellosolve acetate, or the like.

However, as one of ordinary skill in the art will recognize, thematerials listed and described above as examples of materials that maybe utilized for the solvent component of the photoresist 111 are merelyillustrative and are not intended to limit the embodiments. Rather, anysuitable material that may dissolve the polymer resin and the PACs mayalternatively be utilized to help mix and apply the photoresist 111. Allsuch materials are fully intended to be included within the scope of theembodiments.

Additionally, while individual ones of the above described materials maybe used as the solvent for the photoresist 111, in alternativeembodiments more than one of the above described materials may beutilized. For example, the solvent may comprise a combination mixture oftwo or more of the materials described. All such combinations are fullyintended to be included within the scope of the embodiments.

Optionally, a cross-linking agent may also be added to the photoresist111. The cross-linking agent reacts with the polymer resin within thephotoresist 111 after exposure, assisting in increasing thecross-linking density of the photoresist 111, which helps to improve theresist pattern and resistance to dry etching. In an embodiment thecross-linking agent may be an melamine based agent, a urea based agent,ethylene urea based agent, propylene urea based agent, glycoluril basedagent, an aliphatic cyclic hydrocarbon having a hydroxyl group, ahydroxyalkyl group, or a combination of these, oxygen containingderivatives of the aliphatic cyclic hydrocarbon, glycoluril compounds,etherified amino resins, combinations of these, or the like.

Specific examples of materials that may be utilized as a cross-linkingagent include melamine, acetoguanamine, benzoguanamine, urea, ethyleneurea, or glycoluril with formaldehyde, glycoluril with a combination offormaldehyde and a lower alcohol, hexamethoxymethylmelamine,bismethoxymethylurea, bismethoxymethylbismethoxyethylene urea,tetramethoxymethylglycoluril, and tetrabutoxymethylglycoluril, mono-,di-, tri-, or tetra-hydroxymethylated glycoluril, mono-, di-, tri-,and/or tetra-methoxymethylated glycoluril, mono-, di-, tri-, and/ortetra-ethoxymethylated glycoluril, mono-, di-, tri-, and/ortetra-propoxymethylated glycoluril, and mono-, di-, tri-, and/ortetra-butoxymethylated glycoluril,2,3-dihydroxy-5-hydroxymethylnorbornane,2-hydroy-5,6-bis(hydroxymethyl)norbornane, cyclohexanedimethanol,3,4,8(or 9)-trihydroxytricyclodecane, 2-methyl-2-adamantanol,1,4-dioxane-2,3-diol and 1,3,5-trihydroxycyclohexane, tetramethoxymethylglycoluril, methylpropyltetramethoxymethyl glycoluril, andmethylphenyltetramethoxymethylglycoluril,2,6-bis(hydroxymethyl)p-cresol, N-methoxymethyl- orN-butoxymethyl-melamine. Additionally, compounds obtained by reactingformaldehyde, or formaldehyde and lower alcohols with aminogroup-containing compounds, such as melamine, acetoguanamine,benzoguanamine, urea, ethylene urea and glycoluril, and substituting thehydrogen atoms of the amino group with hydroxymethyl group or loweralkoxymethyl group, examples being hexamethoxymethylmelamine,bismethoxymethyl urea, bismethoxymethylbismethoxyethylene urea,tetramethoxymethyl glycoluril and tetrabutoxymethyl glycoluril,copolymers of 3-chloro-2-hydroxypropyl methacrylate and methacrylicacid, copolymers of 3-chloro-2-hydroxypropyl methacrylate and cyclohexylmethacrylate and methacrylic acid, copolymers of3-chloro-2-hydroxypropyl methacrylate and benzyl methacrylate andmethacrylic acid, bisphenol A-di(3-chloro-2-hydroxypropyl)ether,poly(3-chloro-2-hydroxypro-pyl)ether of a phenol novolak resin,pentaerythritol tetra(3-chloro-2-hydroxypropyl)ether, trimethylolmethanetri(3-chloro-2-hydroxypropyl)ether phenol, bisphenolA-di(3-acetoxy-2-hydroxypropyl)ether,poly(3-acetoxy-2-hydroxypropyl)ether of a phenol novolak resin,pentaerythritol tetra(3-acetoxy-2-hydroxypropyl)ether, pentaerythritolpoly(3-chloroacetoxy-2-hydroxypropyl)ether, trimethylolmethanetri(3-acetoxy-2-hydroxypropyl)ether, combinations of these, or the like.

In addition to the polymer resins, the PACs, the solvents, and thecross-linking agents, the photoresist 111 may also include a number ofother additives that will assist the photoresist 111 obtain the highestresolution. For example, the photoresist 111 may also includesurfactants in order to help improve the ability of the photoresist 111to coat the surface on which it is applied. In an embodiment thesurfactants may include nonionic surfactants, polymers havingfluorinated aliphatic groups, surfactants that contain at least onefluorine atom and/or at least one silicon atom, polyoxyethylene alkylethers, polyoxyethylene alkyl aryl ethers,polyoxyethylene-polyoxypropylene block copolymers, sorbitan fatty acidesters, polyoxyethylene sorbitan fatty acid esters.

Specific examples of materials that may be used as surfactants includepolyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene cetyl ether, polyoxyethylene oleyl ether,polyoxyethylene octyl phenol ether, polyoxyethylene nonyl phenol ether,sorbitan monolaurate, sorbitan monopalmitate, sorbitan mono stearate,sorbitan monooleate, sorbitan trioleate, sorbitan tristearate,polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate, polyoxyethylene sorbitan tristearate, polyethyleneglycol distearate, polyethylene glycol dilaurate, polyethylene glycoldilaurate, polyethylene glycol, polypropylene glycol,polyoxyethylenestearyl ether and polyoxyethylene cetyl ether; fluorinecontaining cationic surfactants, fluorine containing nonionicsurfactants, fluorine containing anionic surfactants, cationicsurfactants and anionic surfactants, polyethylene glycol, polypropyleneglycol, polyoxyethylene cetyl ether, combinations of these, or the like.

Another additive that may be added to the photoresist 111 is a quencher,which may be utilized to inhibit diffusion of the generatedacids/bases/free radicals within the photoresist 111, which helps theresist pattern configuration as well as to improve the stability of thephotoresist 111 over time. In an embodiment the quencher is an aminesuch as a second lower aliphatic amine, a tertiary lower aliphaticamine, or the like. Specific examples of amines that may be used includetrimethylamine, diethylamine, triethylamine, di-n-propylamine,tri-n-propylamine, tripentylamine, diethanolamine, and triethanolamine,alkanolamine, combinations of these, or the like.

Alternatively, an organic acid may be utilized as the quencher. Specificembodiments of organic acids that may be utilized include malonic acid,citric acid, malic acid, succinic acid, benzoic acid, salicylic acid,phosphorous oxo acid and its derivatives such as phosphoric acid andderivatives thereof such as its esters, such as phosphoric acid,phosphoric acid di-n-butyl ester and phosphoric acid diphenyl ester;phosphonic acid and derivatives thereof such as its ester, such asphosphonic acid, phosphonic acid dimethyl ester, phosphonic aciddi-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester,and phosphonic acid dibenzyl ester; and phosphinic acid and derivativesthereof such as its esters, including phosphinic acid andphenylphosphinic acid.

Another additive that may be added to the photoresist 111 is astabilizer, which assists in preventing undesired diffusion of the acidsgenerated during exposure of the photoresist 111. In an embodiment thestabilizer may include nitrogenous compounds such as aliphatic primary,secondary, and tertiary amines, cyclic amines such as piperidines,pyrrolidines, morpholines, aromatic heterocycles such as pyridines,pyrimidines, purines, imines such as diazabicycloundecene, guanidines,imides, amides, and others. Alternatively, ammonium salts may also beused for the stabilizer, including ammonium, primary, secondary,tertiary, and quaternary alkyl- and arylammonium salts of alkoxidesincluding hydroxide, phenolates, carboxylates, aryl and alkylsulfonates, sulfonamides, and others. Other cationic nitrogenouscompounds including pyridinium salts and salts of other heterocyclicnitrogenous compounds with anions such as alkoxides including hydroxide,phenolates, carboxylates, aryl and alkyl sulfonates, sulfonamides, andthe like may also be employed.

Yet another additive that may be added to the photoresist 111 may be adissolution inhibitor in order to help control dissolution of thephotoresist 111 during development. In an embodiment bile-salt estersmay be utilized as the dissolution inhibitor. Specific examples ofmaterials that may be utilized include cholic acid (IV), deoxycholicacid (V), lithocholic acid (VI), t-butyl deoxycholate (VII), t-butyllithocholate (VIII), and t-butyl-3-α-acetyl lithocholate (IX).

Another additive that may be added to the photoresist 111 may be aplasticizer. Plasticizers may be used to reduce delamination andcracking between the photoresist 111 and underlying layers (e.g., thelayer to be patterned 109) and may comprise monomeric, loigomeric, andpolymeric plasticizers such as oligo-anpolyethyleneglycol ethers,cycloaliphatic esters, and non-acid reactive steroidally-derivedmaterials. Specific examples of materials that may be used for theplasticizer include dioctyl phthalate, didodecyl phthalate, triethyleneglycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate,dioctyl adipate, dibutyl sebacate, triacetyl glycerine and the like.

Yet another additive that may be added include a coloring agent, whichhelps observers examine the photoresist 111 and find any defects thatmay need to be remedied prior to further processing. In an embodimentthe coloring agent may be either a triarylmethane dye or, alternatively,may be a fine particle organic pigment. Specific examples of materialsthat may be used as coloring agents include crystal violet, methylviolet, ethyl violet, oil blue #603, Victoria Pure Blue BOH, malachitegreen, diamond green, phthalocyanine pigments, azo pigments, carbonblack, titanium oxide, brilliant green dye (C. I. 42020), Victoria PureBlue FGA (Linebrow), Victoria BO (Linebrow) (C. I. 42595), Victoria BlueBO (C. I. 44045) rhodamine 6G (C. I. 45160), Benzophenone compounds suchas 2,4-dihydroxybenzophenone and 2,2′,4,4′-tetrahydroxybenzophenone,salicylic acid compounds such as phenyl salicylate and 4-t-butylphenylsalicylate, phenylacrylate compounds such asethyl-2-cyano-3,3-diphenylacrylate, and2′-ethylhexyl-2-cyano-3,3-diphenylacrylate, benzotriazole compounds suchas 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole, and2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole,coumarin compounds such as 4-methyl-7-diethylamino-1-benzopyran-2-one,thioxanthone compounds such as diethylthioxanthone, stilbene compounds,naphthalic acid compounds, azo dyes, Phthalocyanine blue, phthalocyaninegreen, iodine green, Victoria blue, crystal violet, titanium oxide,carbon black, naphthalene black, Photopia methyl violet, bromphenol blueand bromcresol green, laser dyes such as Rhodamine G6, Coumarin 500, DCM(4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H pyran)),Kiton Red 620, Pyrromethene 580, or the like. Additionally, one or morecoloring agents may be used in combination to provide the desiredcoloring.

Adhesion additives may also be added to the photoresist 111 in order topromote adhesion between the photoresist 111 and an underlying layerupon which the photoresist 111 has been applied (e.g., the layer to bepatterned 109). In an embodiment the adhesion additives include a silanecompound with at least one reactive substituent such as a carboxylgroup, a methacryloyl group, an isocyanate group and/or an epoxy group.Specific examples of the adhesion components include trimethoxysilylbenzoic acid, γ-methacryloxypropyl trimethoxy silane,vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatepropyltriethoxy silane, γ-glycidoxypropyl trimethoxy silane,β-(3,4-epoxycyclohexyl)ethyl trimethoxy silane, benzimidazoles andpolybenzimidazoles, a lower hydroxyalkyl substituted pyridinederivative, a nitrogen heterocyclic compound, urea, thiourea, anorganophosphorus compound, 8-oxyquinoline, 4-hydroxypteridine andderivatives, 1,10-phenanthroline and derivatives, 2,2′-bipyridine andderivatives, benzotriazoles; organophosphorus compounds,phenylenediamine compounds, 2-amino-1-phenylethanol,N-phenylethanolamine, N-ethyldiethanolamine, N-ethylethanolamine andderivatives, benzothiazole, and a benzothiazoleamine salt having acyclohexyl ring and a morpholine ring,3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane,3-methacryloyloxypropyltrimethoxysilane, vinyl trimethoxysilane,combinations of these, or the like.

Surface leveling agents may additionally be added to the photoresist 111in order to assist a top surface of the photoresist 111 to be level sothat impinging light will not be adversely modified by an unlevelsurface. In an embodiment surface leveling agents may includefluoroaliphatic esters, hydroxyl terminated fluorinated polyethers,fluorinated ethylene glycol polymers, silicones, acrylic polymerleveling agents, combinations of these, or the like.

In an embodiment the polymer resin and the PACs, along with any desiredadditives or other agents, are added to the solvent for application.Once added, the mixture is then mixed in order to achieve an evencomposition throughout the photoresist 111 in order to ensure that thereare no defects caused by an uneven mixing or non-constant composition ofthe photoresist 111. Once mixed together, the photoresist 111 may eitherbe stored prior to its usage or else used immediately.

Once ready, the photoresist 111 may be utilized by initially applyingthe photoresist 111 onto the layer to be patterned 109. The photoresist111 may be applied to the layer to be patterned 109 so that thephotoresist 111 coats an upper exposed surface of the layer to bepatterned 109, and may be applied using a process such as a spin-oncoating process, a dip coating method, an air-knife coating method, acurtain coating method, a wire-bar coating method, a gravure coatingmethod, a lamination method, an extrusion coating method, combinationsof these, or the like. In an embodiment the photoresist 111 may beapplied such that it has a thickness over the surface of the layer to bepatterned 109 of between about 10 nm and about 300 nm, such as about 150nm.

Once the photoresist 111 has been applied to the layer to be patterned109, a pre-bake of the photoresist 111 is performed in order to cure anddry the photoresist 111 prior to exposure to finish the application ofthe photoresist 111. The curing and drying of the photoresist 111removes the solvent component while leaving behind the polymer resin,the PACs, cross-linking agents, and the other chosen additives. In anembodiment the pre-bake may be performed at a temperature suitable toevaporate the solvent, such as between about 40° C. and 150° C.,although the precise temperature depends upon the materials chosen forthe photoresist 111. The pre-bake is performed for a time sufficient tocure and dry the photoresist 111, such as between about 10 seconds toabout 5 minutes, such as about 90 seconds.

FIG. 6 illustrates an exposure of the photoresist 111 to form an exposedregion 601 and an unexposed region 603 within the photoresist 111. In anembodiment the exposure may be initiated by placing the semiconductordevice 100 and the photoresist 111, once cured and dried, into animaging device 600 for exposure. The imaging device 600 may comprise asupport plate 605, an energy source 607, a patterned mask 609 betweenthe support plate 605 and the energy source 607, and optics 613. In anembodiment the support plate 605 is a surface to which the semiconductordevice 100 and the photoresist 111 may be placed or attached to andwhich provides support and control to the substrate 101 during exposureof the photoresist 111. Additionally, the support plate 605 may bemovable along one or more axes, as well as providing any desired heatingor cooling to the substrate 101 and photoresist 111 in order to preventtemperature gradients from affecting the exposure process.

In an embodiment the energy source 607 supplies energy 611 such as lightto the photoresist 111 in order to induce a reaction of the PACs, whichin turn reacts with the polymer resin to chemically alter those portionsof the photoresist 111 to which the energy 611 impinges. In anembodiment the energy 611 may be electromagnetic radiation, such asg-rays (with a wavelength of about 436 nm), i-rays (with a wavelength ofabout 365 nm), ultraviolet radiation, far ultraviolet radiation, x-rays,electron beams, or the like. The energy source 607 may be a source ofthe electromagnetic radiation, and may be a KrF excimer laser light(with a wavelength of 248 nm), an ArF excimer laser light (with awavelength of 193 nm), a F2 excimer laser light (with a wavelength of157 nm), or the like, although any other suitable source of energy 611,such as mercury vapor lamps, xenon lamps, carbon arc lamps or the like,may alternatively be utilized.

The patterned mask 609 is located between the energy source 607 and thephotoresist 111 in order to block portions of the energy 611 to form apatterned energy 615 prior to the energy 611 actually impinging upon thephotoresist 111. In an embodiment the patterned mask 609 may comprise aseries of layers (e.g., substrate, absorbance layers, anti-reflectivecoating layers, shielding layers, etc.) to reflect, absorb, or otherwiseblock portions of the energy 611 from reaching those portions of thephotoresist 111 which are not desired to be illuminated. The desiredpattern may be formed in the patterned mask 609 by forming openingsthrough the patterned mask 609 in the desired shape of illumination.

Optics (represented in FIG. 6 by the trapezoid labeled 613) may be usedto concentrate, expand, reflect, or otherwise control the energy 611 asit leaves the energy source 607, is patterned by the patterned mask 609,and is directed towards the photoresist 111. In an embodiment the optics613 comprise one or more lenses, mirrors, filters, combinations ofthese, or the like to control the energy 611 along its path.Additionally, while the optics 613 are illustrated in FIG. 6 as beingbetween the patterned mask 609 and the photoresist 111, elements of theoptics 613 (e.g., individual lenses, mirrors, etc.) may also be locatedat any location between the energy source 607 (where the energy 611 isgenerated) and the photoresist 111.

In an embodiment the semiconductor device 100 with the photoresist 111is placed on the support plate 605. Once the pattern has been aligned tothe semiconductor device 100, the energy source 607 generates thedesired energy 611 (e.g., light) which passes through the patterned mask609 and the optics 613 on its way to the photoresist 111. The patternedenergy 615 impinging upon portions of the photoresist 111 induces areaction of the PACs within the photoresist 111. The chemical reactionproducts of the PACs' absorption of the patterned energy 615 (e.g.,acids/bases/free radicals) then reacts with the polymer resin,chemically altering the photoresist 111 in those portions that wereilluminated through the patterned mask 609.

In a specific example in which the patterned energy 615 is a 193 nmwavelength of light, the PAC is a photoacid generator, and the bulkygroup to be decomposed 203 is an acid leaving group on the hydrocarbonstructure and a cross linking agent is used, the patterned energy 615will impinge upon the photoacid generator and the photoacid generatorwill absorb the impinging patterned energy 615. This absorptioninitiates the photoacid generator to generate a proton (e.g., a H+ atom)within the photoresist 111. When the proton impacts the bulky group tobe decomposed 203 on the hydrocarbon structure, the proton will reactwith the bulky group to be decomposed 203, cleaving the bulky group tobe decomposed 203 from the hydrocarbon structure, and altering theproperties of the polymer resin in general. The bulky group to bedecomposed 203 can then degas from the photoresist 111 eitherimmediately during the exposure process or during the post-exposurebaking process (described below), thereby causing a mass loss of thephotoresist 111, which shrinks in size and caused a deterioration of thecritical dimensions of the pattern.

However, by additionally using the small group which will decompose 209along with the bulky group which will decompose 203, such a mass losscan be reduced. In particular, during the exposure in the embodimentdescribed above, in addition to the protons from the PACs impacting uponthe bulky group which will decompose 203, the protons will also impactupon the small group which will decompose, causing it to also cleavefrom the hydrocarbon structure and degas during either the exposureprocess or the post-exposure baking process. However, because the smallgroup which will decompose 209 has fewer atoms than the bulky groupwhich will decompose 203, the overall mass loss from a single smallgroup which will decompose is much less than from a single bulky groupwhich will decompose 209. As such, by utilizing the small group whichwill decompose 209 in addition to the bulky group which will decompose203, the overall mass loss and critical dimension deterioration can bereduced.

Alternatively, in the embodiment described above with respect to FIG. 3in which a bulky group which will not decompose 301 is utilized in placeof the small group which will decompose 209, the patterned energy 615from the exposure will impinge upon the PACs and generate the protons,which will then react with the bulky group which decompose 203, causingit to cleave and leave the photoresist 111 with the bulky group whichwill not decompose 301 remaining on the hydrocarbon backbone. However,with the addition of the bulky group which will not decompose 301, theoverall percentage of mass loss from the bulky group which willdecompose 203 will be reduced, as the overall mass of the polymer resinis increased due to the presence of the bulky group which will decompose301.

In the embodiment described above with respect to FIG. 4, in which thesmall group which will decompose 209 is attached to the bulky groupwhich will not decompose 301, the patterned energy 615 will impinge uponthe PACs to generate the protons, which will then react with the bulkygroup which will decompose 203 as well as the small group which willdecompose 209, causing these groups to cleave from the hydrocarbonstructure and eventually degas from the photoresist 111. However, byusing the small group which will decompose 209 to reduce the amount ofmaterial that leaves as well as by using the bulky group which will notdecompose 301 to increase the amount of material that will remain, theoverall mass loss and its accompanying shrinkage and deterioration ofthe critical dimension will be reduced.

Finally, in the embodiment described above with respect to FIG. 4, inwhich a polar functional group is part of the polymer resin, thepatterned energy 615 will impinge upon the PACs to generate the protons,which will then impact upon the bulky group which will decompose 203.However, the presence of the polar functional group will retard anddecrease any diffusion of the protons (or bases or free radicals) awayfrom the exposed region 601 of the photoresist 111. Such a reduction indiffusion will prevent the protons from reacting any further and causingundesired outgassing of by-products from the unexposed portion 603 ofthe photoresist 111. Such a prevention can help reduce the mass loss andshrinkage of the photoresist 111.

Returning to FIG. 6, the exposure of the photoresist 111 may optionallyoccur using an immersion lithography technique. In such a technique animmersion medium (not individually illustrated in FIG. 6) may be placedbetween the imaging device 600 (and particularly between a final lens ofthe optics 613) and the photoresist 111. With this immersion medium inplace, the photoresist 111 may be patterned with the patterned energy615 passing through the immersion medium.

In this embodiment a protective layer (also not individually illustratedin FIG. 6) may be formed over the photoresist 111 in order to preventthe immersion medium from coming into direct contact with thephotoresist 111 and leaching or otherwise adversely affecting thephotoresist 111. In an embodiment the protective layer is insolublewithin the immersion medium such that the immersion medium will notdissolve it and is immiscible in the photoresist 111 such that theprotective layer will not adversely affect the photoresist 111.Additionally, the protective layer is transparent so that the patternedenergy 615 may pass through the protective layer.

In an embodiment the protective layer comprises a protective layer resinwithin a protective layer solvent. The material used for the protectivelayer solvent is, at least in part, dependent upon the components chosenfor the photoresist 111, as the protective layer solvent should notdissolve the materials of the photoresist 111 so as to avoid degradationof the photoresist 111 during application and use of the protectivelayer. In an embodiment the protective layer solvent includes alcoholsolvents, fluorinated solvents, and hydrocarbon solvents.

Specific examples of materials that may be utilized for the protectivelayer solvent include methanol, ethanol, 1-propanol, isopropanol,n-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol,3-methyl-1-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol,2-pentanol, 3-pentanol, n-hexanol, cyclohecanol, 1-hexanol, 1-heptanol,1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol,3-octanol, 4-octanol, 2-methyl-2-butanol, 3-methyl-1-butanol,3-methyl-2-butanol, 2-methyl-1-butanol, 2-methyl-1-pentanol,2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol,3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol,4-methyl-2-pentanol, 2,2,3,3,4,4-hexafluoro-1-butanol,2,2,3,3,4,4,5,5-octafluoro-1-pentanol,2,2,3,3,4,4,5,5,6,6-decafluoro-1-hexanol,2,2,3,3,4,4-hexafluoro-1,5-pentanediol,2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol,2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-diol, 2-fluoroanisole,2,3-difluoroanisole, perfluorohexane, perfluoroheptane,perfluoro-2-pentanone, perfluoro-2-butyltetrahydrofuran,perfluorotetrahydrofuran, perfluorotributylamine,perfluorotetrapentylamine, toluene, xylene and anisole, and aliphatichydrocarbon solvents, such as n-heptane, n-nonane, n-octane, n-decane,2-methylheptane, 3-methylheptane, 3,3-dimethylhexane,2,3,4-trimethylpentane, combinations of these, or the like.

The protective layer resin may comprise a protective layer repeatingunit. In an embodiment the protective layer repeating unit may be anacrylic resin with a repeating hydrocarbon structure having a carboxylgroup, an alicyclic structure, an alkyl group having one to five carbonatoms, a phenol group, or a fluorine atom-containing group. Specificexamples of the alicyclic structure include a cyclohexyl group, anadamantyl group, a norbornyl group, a isobornyl group, a tricyclodecylgroup, a tetracyclododecyl group, and the like. Specific examples of thealkyl group include an n-butyl group, an isobutyl group, or the like.However, any suitable protective layer resin may alternatively beutilized.

The protective layer composition may also include additional additivesto assist in such things as adhesion, surface leveling, coating, and thelike. For example, the protective layer composition may further comprisea protective layer surfactant, although other additives may also beadded, and all such additions are fully intended to be included withinthe scope of the embodiment. In an embodiment the protective layersurfactant may be a alkyl cationic surfactant, an amide-type quaternarycationic surfactant, an ester-type quaternary cationic surfactant, anamine oxide surfactant, a betaine surfactant, an alkoxylate surfactant,a fatty acid ester surfactant, an amide surfactant, an alcoholsurfactant, an ethylenediamine surfactant, or a fluorine- and/orsilicon-containing surfactant.

Specific examples of materials that may be used for the protective layersurfactant include polyoxyethylene alkyl ethers, such as polyoxyethylenelauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl etherand polyoxyethylene oleyl ether; polyoxyethylene alkyl aryl ethers, suchas polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenolether; polyoxyethylene-polyooxypropylene block copolymers; sorbitanfatty acid esters, such as sorbitan monolaurate, sorbitan monopalmitate,sorbitan monostearate, sorbitan monooleate, sorbitan trioleate andsorbitan tristearate; and polyoxyethylene sorbitan monolaurate,polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitanmonostearate, polyoxyethylene sorbitan trioleate and polyoxyethylenesorbitan tristearate.

Prior to application of the protective layer onto the photoresist 111,the protective layer resin and desired additives are first added to theprotective layer solvent to form a protective layer composition. Theprotective layer solvent is then mixed to ensure that the protectivelayer composition has a consistent concentration throughout theprotective layer composition.

Once the protective layer composition is ready for application, theprotective layer composition may be applied over the photoresist 111. Inan embodiment the application may be performed using a process such as aspin-on coating process, a dip coating method, an air-knife coatingmethod, a curtain coating method, a wire-bar coating method, a gravurecoating method, a lamination method, an extrusion coating method,combinations of these, or the like. In an embodiment the photoresist 111may be applied such that it has a thickness over the surface of thephotoresist 111 of about 100 nm.

After the protective layer composition has been applied to thephotoresist 111, a protective layer pre-bake may be performed in orderto remove the protective layer solvent. In an embodiment the protectivelayer pre-bake may be performed at a temperature suitable to evaporatethe protective layer solvent, such as between about 40° C. and 150° C.,although the precise temperature depends upon the materials chosen forthe protective layer composition. The protective layer pre-bake isperformed for a time sufficient to cure and dry the protective layercomposition, such as between about 10 seconds to about 5 minutes, suchas about 90 seconds.

Once the protective layer has been placed over the photoresist 111, thesemiconductor device 100 with the photoresist 111 and the protectivelayer are placed on the support plate 605, and the immersion medium maybe placed between the protective layer and the optics 613. In anembodiment the immersion medium is a liquid having a refractive indexgreater than that of the surrounding atmosphere, such as having arefractive index greater than 1. Examples of the immersion medium mayinclude water, oil, glycerine, glycerol, cycloalkanols, or the like,although any suitable medium may alternatively be utilized.

The placement of the immersion medium between the protective layer andthe optics 613 may be done using, e.g., an air knife method, wherebyfresh immersion medium is applied to a region between the protectivelayer and the optics 613 and controlled using pressurized gas directedtowards the protective layer to form a barrier and keep the immersionmedium from spreading. In this embodiment the immersion medium may beapplied, used, and removed from the protective layer for recycling sothat there is fresh immersion medium used for the actual imagingprocess.

However, the air knife method described above is not the only method bywhich the photoresist 111 may be exposed using an immersion method. Anyother suitable method for imaging the photoresist 111 using an immersionmedium, such as immersing the entire substrate 101 along with thephotoresist 111 and the protective layer, using solid barriers insteadof gaseous barriers, or using an immersion medium without a protectivelayer, may also be utilized. Any suitable method for exposing thephotoresist 111 through the immersion medium may be used, and all suchmethods are fully intended to be included within the scope of theembodiments.

After the photoresist 111 has been exposed to the patterned energy 615,a post-exposure baking may be used in order to assist in the generating,dispersing, and reacting of the acid/base/free radical generated fromthe impingement of the patterned energy 615 upon the PACs during theexposure. Such assistance helps to create or enhance chemical reactionswhich generate chemical differences between the exposed region 601 andthe unexposed region 603 within the photoresist 111. These chemicaldifferences also cause differences in the solubility between the exposedregion 601 and the unexposed region 603. In an embodiment thispost-exposure baking may occur at temperatures of between about 50° C.and about 160° C. for a period of between about 40 seconds and about 120seconds.

FIG. 7 illustrates a development of the photoresist 111 with the use ofa developer 701 after the photoresist 111 has been exposed. After thephotoresist 111 has been exposed and the post-exposure baking hasoccurred, the photoresist 111 may be developed using either a negativetone developer or a positive tone developer, depending upon the desiredpattern for the photoresist 111. In an embodiment in which the unexposedregion 603 of the photoresist 111 is desired to be removed to form anegative tone, a negative tone developer such as an organic solvent orcritical fluid may be utilized to remove those portions of thephotoresist 111 which were not exposed to the patterned energy 615 and,as such, retain their original solubility. Specific examples ofmaterials that may be utilized include hydrocarbon solvents, alcoholsolvents, ether solvents, ester solvents, critical fluids, combinationsof these, or the like. Specific examples of materials that can be usedfor the negative tone solvent include hexane, heptane, octane, toluene,xylene, dichloromethane, chloroform, carbon tetrachloride,trichloroethylene, methanol, ethanol, propanol, butanol, critical carbondioxide, diethyl ether, dipropyl ether, dibutyl ether, ethyl vinylether, dioxane, propylene oxide, tetrahydrofuran, cellosolve, methylcellosolve, butyl cellosolve, methyl carbitol, diethylene glycolmonoethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone,isophorone, cyclohexanone, methyl acetate, ethyl acetate, propylacetate, butyl acetate, pyridine, formamide, N,N-dimethyl formamide, orthe like.

If a positive tone development is desired, a positive tone developersuch as a basic aqueous solution may be utilized to remove thoseportions of the photoresist 111 which were exposed to the patternedenergy 615 and which have had their solubility modified and changedthrough the chemical reactions. Such basic aqueous solutions may includetetra methyl ammonium hydroxide (TMAH), tetra butyl ammonium hydroxide,sodium hydroxide, potassium hydroxide, sodium carbonate, sodiumbicarbonate, sodium silicate, sodium metasilicate, aqueous ammonia,monomethylamine, dimethylamine, trimethylamine, monoethylamine,diethylamine, triethylamine, monoisopropylamine, diisopropylamine,triisopropylamine, monobutylamine, dibutylamine, monoethanolamine,diethanolamine, triethanolamine, dimethylaminoethanol,diethylaminoethanol, ammonia, caustic soda, caustic potash, sodiummetasilicate, potassium metasilicate, sodium carbonate,tetraethylammonium hydroxide, combinations of these, or the like.

However, as one of ordinary skill in the art will recognize, the abovedescription of positive tone developers and negative tone developers areonly intended to be illustrative and are not intended to limit theembodiments to only the developers listed above. Rather, any suitabletype of developer, including acid developers or even water developers,that may be utilized to selectively remove a portion of the photoresist111 that has a different property (e.g., solubility) than anotherportion of the photoresist 111, may alternatively be utilized, and allsuch developers are fully intended to be included within the scope ofthe embodiments.

In an embodiment in which immersion lithography is utilized to exposethe photoresist 111 and a protective layer is utilized to protect thephotoresist 111 from the immersion medium, the developer 701 may bechosen to remove not only those portions of the photoresist 111 that aredesired to be removed, but may also be chosen to remove the protectivelayer in the same development step. Alternatively, the protective layermay be removed in a separate process, such as by a separate solvent fromthe developer 701 or even an etching process to remove the protectivelayer from the photoresist 111 prior to development.

FIG. 7 illustrates an application of the developer 701 to thephotoresist 111 using, e.g., a spin-on process. In this process thedeveloper 701 is applied to the photoresist 111 from above thephotoresist 111 while the semiconductor device 100 (and the photoresist111) is rotated. In an embodiment the developer 701 may be supplied at aflow rate of between about 10 ml/min and about 2000 ml/min, such asabout 1000 ml/min, while the semiconductor device 100 is being rotatedat a speed of between about 100 rpm and about 3500 rpm, such as about1500 rpm. In an embodiment the developer 701 may be at a temperature ofbetween about 10° C. and about 80° C., such as about 50° C., and thedevelopment may continue for between about 1 minute to about 60 minutes,such as about 30 minutes.

However, while the spin-on method described herein is one suitablemethod for developing the photoresist 111 after exposure, it is intendedto be illustrative and is not intended to limit the embodiments. Rather,any suitable method for development, including dip processes, puddleprocesses, spray-on processes, combinations of these, or the like, mayalternatively be used. All such development processes are fully intendedto be included within the scope of the embodiments.

FIG. 7 illustrates a cross-section of the development process in which anegative tone developer is utilized. As illustrated, the developer 701is applied to the photoresist 111 and dissolves the unexposed portion603 of the photoresist 111. This dissolving and removing of theunexposed portion 603 of the photoresist 111 leaves behind an openingwithin the photoresist 111 that patterns the photoresist 111 in theshape of the patterned energy 615, thereby transferring the pattern ofthe patterned mask 609 to the photoresist 111.

FIG. 8 illustrates a removal of the developer 701 and the photoresist111 after it has been developed with the developer 701. In an embodimentthe developer 701 may be removed using, e.g., a spin-dry process,although any suitable removal technique may alternatively be utilized.After the photoresist 111 has been developed additional processing maybe performed on the layer to be patterned 109 while the photoresist 111is in place. As one example, a reactive ion etch or other etchingprocess may be utilized to transfer the pattern of the photoresist 111to the underlying layer to be patterned 109. Alternatively, in anembodiment in which the layer to be patterned 109 is a seed layer, thelayer to be patterned 109 may be plated in order to form, e.g., a copperpillar, or other conductive structure in the opening of the photoresist111. Any suitable processing, whether additive or subtractive, that maybe performed while the photoresist 111 is in place may be performed, andall such additional processing are fully intended to be included withinthe scope of the embodiments.

Once the layer to be patterned 109 has been patterned using thephotoresist 111, the photoresist may be removed from the layer to bepatterned 109 (not separately illustrated in FIG. 8). In an embodimentan ashing process may be utilized in order to remove the photoresist111, whereby the temperature of the photoresist 111 is increased tocause a thermal breakdown of the photoresist 111, which can then beremoved using a cleaning procedure such as a rinse. Alternatively thephotoresists 111 may be removed using, e.g., a wet etching process. Anysuitable method for removing the photoresist 111 may be used, and allsuch methods are fully intended to be included within the scope of theembodiment.

By utilizing the additional structures on the hydrocarbon backbone asdiscussed in the above described embodiments, each embodiment canindependently decrease shrinkage of the photoresist 111 below 20% afterthe post-exposure baking. Such a reduction in the shrinkage reduces thedeterioration of the critical dimensions of the photoresist 111 andallows for smaller and smaller images to be formed within thephotoresist 111.

In accordance with an embodiment, a photoresist comprising a hydrocarbonbackbone and a first group which will decompose is provided. The firstgroup which will decompose has a first number of carbon atoms. Thephotoresist also has a second group which will decompose, the secondgroup which will decompose having a second number of carbon atomssmaller than the first number of carbon atoms and smaller than ninecarbon atoms.

In accordance with another embodiment, a photoresist comprising asolvent, a photoactive compound, and a polymer resin is provided. Thepolymer resin further comprises a first group which will decompose thathas no more than 9 carbon atoms, and a second group which will decomposethat has greater than nine carbon atoms.

In accordance with yet another embodiment, a method of manufacturing asemiconductor device comprising applying a photoresist to a layer to bepatterned is provided. The photoresist comprises a hydrocarbon backbone,a first group which will decompose, wherein the first group which willdecompose comprises greater than 9 carbon atoms, and a second groupwhich will decompose, wherein the second group which will decomposecomprises no greater than 9 carbon atoms. The photoresist is exposed toa patterned light source, and the photoresist is developed after theexposing the photoresist.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method of manufacturing a semiconductor device, the method comprising: applying a photoresist to a layer to be patterned, wherein the photoresist comprises a singular polymer, the singular polymer comprising: a hydrocarbon backbone; a first acid labile group, wherein the first acid labile group has less than 9 carbon atoms, wherein the first acid labile group comprises a cycloalkyl group and further comprises a C4-C5 alkyl group, an acetyl group, or an acetyl alkyl group; and a second acid labile group, wherein the second acid labile group comprises greater than 9 carbon atoms; exposing the photoresist to a patterned light source; and developing the photoresist after the exposing the photoresist.
 2. The method of claim 1, wherein the developing the photoresist further comprises applying a negative tone developer to the photoresist after the exposing the photoresist.
 3. The method of claim 1, wherein the singular polymer further comprises a bulky group which will not decompose, wherein the bulky group which will not decompose comprises greater than 9 carbon atoms.
 4. The method of claim 3, wherein the bulky group which will not decompose has a loading of greater than 5%.
 5. The method of claim 1, wherein after the exposing the photoresist to the patterned light source, the first acid labile group and the second acid labile group cleave from the hydrocarbon backbone and degas from the photoresist.
 6. The method of claim 1, wherein repeating units comprising the first acid labile group are present in an amount of greater than 5% of all of the repeating units present within the singular polymer.
 7. The method of claim 1, further comprising a third group which will not decompose, the third group which will not decompose being bonded to the first acid labile group.
 8. The method of claim 7, wherein repeating units comprising the third group which will not decompose are present in an amount of greater than 5% of all of the repeating units present within the singular polymer.
 9. The method of claim 1, wherein repeating units comprising the second acid labile group are present in an amount of greater than 30% of all of the repeating units present within the singular polymer.
 10. A method comprising: forming a layer to be patterned over a metallization layer; depositing a photoresist on the layer to be patterned, the photoresist comprising a polymer resin, a photoactive compound, and a solvent, the polymer resin comprising: a hydrocarbon backbone; a bulky leaving group having more than nine carbon atoms and bonded to the hydrocarbon backbone; a group which will not decompose bonded to the hydrocarbon backbone; and a small leaving group having less than nine carbon atoms, the small leaving group comprising a cycloalkyl group and one of a C4-C5 alkyl group, an acetyl group, or an acetyl alkyl group, the small leaving group being bonded to the hydrocarbon backbone through the group which will not decompose; exposing the photoresist to a patterned energy source to form an exposed region and an unexposed region, wherein the photoactive compound generates acids, bases, or free radicals in the exposed region, wherein the acids, the bases, or the free radicals cleave the bulky leaving group from the hydrocarbon backbone and cleave the small leaving group from the group which will not decompose in the exposed region; and developing the photoresist to remove the photoresist from the exposed region or the unexposed region.
 11. The method of claim 10, wherein the group which will not decompose comprises an alkyl chain, an alkyl ring, or a three-dimensional alkyl structure having between 9 and 30 carbon atoms.
 12. The method of claim 10, wherein a combined loading of the group which will not decompose and the small leaving group is greater than 5% of an overall loading on the hydrocarbon backbone.
 13. The method of claim 10, wherein the polymer resin further comprises a lactone group, and wherein the lactone group has a loading of between 30% and 70%.
 14. The method of claim 10, wherein the polymer resin further comprises an adhesive group, wherein the adhesive group is polar, and wherein the adhesive group has a loading of less than 20%.
 15. A method comprising: exposing a photoresist to a patterned energy source, the photoresist comprising a polymer resin, the polymer resin comprising a bulky leaving group and a cleavage unit bonded to a hydrocarbon backbone, wherein: the bulky leaving group has a loading of greater than 45% and comprises more than nine carbon atoms; the cleavage unit has a loading of greater than 5%, has less than 9 carbon atoms, and comprises a cycloalkyl group and a C4-C5 alkyl group; and the exposing the photoresist to the patterned energy source cleaves the bulky leaving group and the cleavage unit from the hydrocarbon backbone; and removing an exposed portion of the photoresist or an unexposed portion of the photoresist using a developer.
 16. The method of claim 15, wherein the cleavage unit has the following structure:


17. The method of claim 15, wherein the cleavage unit has the following structure:


18. The method of claim 15, wherein the cleavage unit has the following structure:

wherein Rd is a C0-C1 alkyl group.
 19. The method of claim 15, wherein the cleavage unit has the following structure:


20. The method of claim 15, wherein the cleavage unit has the following structure:

wherein Rd is a C0-C1 alkyl group. 